Electronic components used in the manufacture of electronic devices must often be stored within a factory environment for an extended period of time before their use. Some components are susceptible to moisture absorption which can adversely impact the utility of these components. Rapid evaporation of the absorbed moisture during assembly operations involving intense heat, such as a solder reflow operation, may cause delamination of the various layers of material which make up the component. The period of exposure to moisture which a component can sustain while still maintaining its utility is called the shelf life of the component. A typical shelf life of a component exposed to a moisture content of 85 percent humidity at 85 degrees Fahrenheit is approximately 96 hours. Consequently, these components are usually stored in a moisture controlled environment, such as a dry box, or the like. When the availability of the components is required for assembly operations within the factory, the components are often removed from the moisture controlled environment and placed in a convenient location for an assembly operation.
A typical assembly process may include automatic part placement machines operating at a high part placement rate. Many of these machines use a parts feeding system in which the components are mounted on a reel to facilitate automatic placement. The reeled components are removed from storage in a moisture controlled environment and installed into the parts feeding system when required for assembly. Once placed in the feeder system, the components are exposed to moisture present in the factory environment. Depending on the frequency of use and the number of components on a reel, the components may exceed their shelf life before being used for assembly. Hence, the components may become unusable until the moisture is removed, if this is possible.
Attempts to solve this problem include placing the part placement machine in an enclosure for which the moisture content is controlled, and enclosing the entire parts feeding system in a moisture controlled environment. Neither of these solutions has produced satisfactory results. One major factor is the cost involved in maintaining the moisture content control while accommodating the frequent environment breaches which occur because of parts swapping and feeder system maintenance. Another factor is that the bulk of these enclosures may interfere with normal manufacturing operations.
There may be a significant adverse impact on manufacturing efficiency and cost because of the problems associated with the moisture content of components. A solution which reduces or eliminates moisture absorption by components, especially with respect to a reeled components parts feeding system, is needed.